if 5>2:
    print("5 is greater than 2")
    print("22222")
else:
    print("5 is less than 2")


age=30
if age<18:
    print("you are underaged")
elif age>=18 and age<=30:
    print("you are young")
elif age>=30 and age<=50:
    print("you are middle-aged")
else:
    print("you are old")


year=int(input("enter year:"))
if (year%4==0 and year%100!=0) or (year%400==0):
    print("d%是闰年"%year)
else:
    print("d%不是闰年"%year)


a=int(input("enter a:"))
b=int(input("enter b:"))
c=int(input("enter c:"))
if a>b:
    if a>c:
        print("a is the largest")
    else:
        print("c is the largest")
else:
    if b>c:
        print("b is the largest")
    else:
        print("c is the largest")


num1=float(input("enter num1:"))
num2=float(input("enter num2:"))
op=input("enter op:")
if op=="+":
    print(num1+num2)
elif op=="-":
    print(num1-num2)
elif op=="*":
    print(num1*num2)
elif op=="/":
    print(num1/num2)
else:
    print("输入错误")

